Intraoperative Frozen Section Analysis for the Excision of Nonmelanoma Skin Cancer: A Single-center Experience

Abstract

INTRODUCTION: Recurrence rates for nonmelanoma skin cancers (NMSCs) following Mohs’ micrographic surgery (MMS) are consistently lower than standard surgical excision. However, variations in the availability of MMS, waiting times, and costs continue to affect patient preference between treatment modalities. Furthermore, MMS commonly requires delayed reconstruction leading to additional surgeries that increases the risk of adverse outcomes. To achieve curative resection while ensuring optimal cosmetic outcomes, plastic surgeons may utilize intraoperative frozen section-guided excision to forego extensive or delayed reconstruction. METHODS: Patients presenting with NMSCs undergoing wide local excision using intraoperative frozen section margin analysis (IFSA) at our institution from October 2008 to November 2016 were retrospectively reviewed. Analyzed data included IFSA results, final permanent section histopathology, number of resections required for clear margins, and recurrence rates. Excisions were performed by 1 of 3 plastic surgeons and analyzed by 1 of 8 pathologists. RESULTS: A total of 171 patients and 204 lesions were included in the study. Mean patient age was 72 years. Operative reports demonstrated that 79.9% of margins were clear after one excision. The remaining 20.1% of cases with residual positive margins after primary excision were identified using IFSA and were re-excised until negative margins were achieved. Of the 20.1%, a total of 11.8% required a second excision and 8.3% required ≥3 excisions. Intraoperative frozen section results revealed 1 false-positive case representing a rate of 0.49% and 5 false-negative results leading to a rate of 2.45%. Fifteen patients had local recurrence; a rate of 7.35%. Frozen section sensitivity was 89.79% and specificity was 99.35%. The positive predictive value was 97.78% with a negative predictive value of 96.85%. Patients had a mean follow-up of 39 months. CONCLUSION: The resection results and recurrence rate of NMSCs excised at our institution are comparable to national trends using standard surgical excision. The findings suggest that standard surgical excision using intraoperative frozen section analysis is a safe and effective alternative to MMS.